I just did this for the first time- it was easy and I had great results!

First, I picked up an unpasteurized bottle of kombucha. I couldn't find a plain one, so I used elderflower. I avoided the fruit flavored ones, because I wasn't sure how the added fruit juice would do in a ferment.

I shook it up (to get the sediment on the bottom) and put it in a covered jar with a cup or so of sweet tea....and waited. I swirled it every now and then, although I'm not sure that was necessary. Once it got very strong smelling, I added some more sweet tea, and within a week had a film starting to develop. I stopped swirling and kept adding tea, and now the mother is thick and healthy, only two or three weeks later! It's pretty strong smelling now, so soon I'll get the first actual batch out of it.
Can't wait!

Has anyone else used bottled 'buch for their starter? How was your process different? I'd love to hear other stories to figure out the best way to accomplish this. Seems like a lot of people want mothers and aren't able to find them.